VW is seeking as much as 20 billion euros ($21.18 billion) in funding from banks as it struggles to cope with the expected costs of the scandal, which analysts say could top 40 billion euros including fines, legal claims and vehicle refits.

But while the total costs of the scandal aren't clear, VW has no plans to alter the existing provisions, a spokesman told reporters on Wednesday at the carmaker's base in Wolfsburg.

VW said during a presentation it only needs to install a mesh near the air cleaner in 3 million 1.6-litre EA 189 diesel engines to ensure they comply with EU emissions rules.

Fitting the mesh will require one hour of work, improving the measuring capability of the engine's air mass sensor which enables more efficient combustion, another spokesman said.

Chief Executive Matthias Mueller told managers on Monday that the technical steps needed to fix the vehicles are "technically and financially manageable."

VW said it was too early to give an estimate of the costs of installing the so-called air flow transformer. All 8.5 million engines in Europe, including 5.2 million 2.0-litre diesels and 300,000 1.2-litre diesels, will require software updates.

"Our assumption that fundamental interferences with the engine are necessary have not come true," Mueller said.